In manufacturing, a moving surface, such as a conveyor belt, is often used to transport an object from one place to another. Often, the location of the object or objects upon the moving surface is critical. This is especially true when the moving surface is serving as a product infeed device for providing objects, such as raw materials, to a machine for processing. For instance, the moving surface may be acting as an infeed conveyor belt for a portioning machine, wherein objects or workpieces, such as chicken breasts, placed upon the conveyor belt are further processed, for example, trimmed or portioned. For efficient trimming or portioning, it is important to place the workpieces onto the belt in a particular manner with correct spacing between workpieces. If the workpieces are placed on the conveyor belt too close to each other, it may not be possible for a portioner to accurately cut the workpieces. If the workpieces are placed too far apart, then the full capacity of the portioning machine is not utilized. Further, it is often desirable to place the workpiece in a particular orientation on the belt for more efficient portioning. Further still, the selected placement parameters, such as spacing, orientation, etc., may change at any time.
In one previously developed system, a static laser is used to form a straight line down the belt along which the workpieces to be portioned are to be placed. The worker is instructed to place the workpieces at a certain distance from each other along the line. However, significant errors in placement often occur, since it may be difficult for the workers to position the workpieces at a uniform spacing along the line. Also, often workers experience difficulty in aligning the workpieces laterally along the belt with sufficient precision so that the side-to-side location of the workpieces on the belt is accurate. This can also reduce the efficiency of the portioning machine. Further, the line does not provide the worker with orientation information. In other words, the line does not indicate to the worker how the product should be oriented when placed upon the belt.
In another previously developed system, a grid is permanently printed upon the conveyor belt, thereby providing some guidance as to where the workpieces to be portioned should be placed. For instance, a worker may be instructed to place the workpieces at an intersection of certain grid lines, or within a selected square of the grid. However, significant errors in placement often occur, since it may be difficult for the workers to accurately center the workpieces upon an intersection of grid lines, or within a particular square of the grid.
Like the above described previously developed system, the inaccurate placement of the workpieces upon the conveyor belt reduces the efficiency of the portioning machine. Further, the grid does not provide the worker with orientation information. In other words, the line does not indicate to the worker how the product should be oriented when placed upon the belt, only where. Further, since the grid is permanently printed upon the conveyor belt, the grid is static in nature and can not be dynamically adjusted to accommodate different shaped workpieces or changes in placement parameters.
Thus, there exists a need for a method and apparatus for indexing objects upon a moving surface that indicates to a worker the correct spacing and/or orientation of an object to be placed upon a moving surface that is economical to manufacture, has a high degree of reliability, and satisfies the performance expectations of the end user.